I. Field of the Invention
This invention relates generally to highway traffic control systems, and more particularly to an automated gate operations system for controlling vehicle traffic flow at freeway interchanges, whereby traffic can be excluded from predetermined segments of the freeway.
II. Discussion of the Prior Art
In the event of ice storms or heavy snowstorms, it may prove dangerous, or even life-threatening, to allow vehicles to drive on ice and/or snow-covered freeways. Then, too, the job of snow and ice removal is greatly facilitated if the freeway stretches to be cleared are free of traffic. With passenger cars and commercial vehicles absent, multiple highway maintenance trucks equipped with plows and sand spreaders can drive in parallel to span all freeway lanes from a shoulder to a median strip to clear ice and snow in one pass. The trucks can travel at a relatively high speed, which cannot be done if the maintenance vehicles must maneuver to avoid other vehicles.
In shutting down a section of freeway to traffic, it has been the past practice, in regions where snow and ice are common, to provide manually operable gates having a barrier arm which would typically be lowered across freeway entrance ramps and across the freeway driving lanes by state highway patrol personnel upon receiving a verbal broadcast message from an authorized official of the state""s Department of Transportation.
It has also been the past practice to have warning signs positioned up road from the freeway exit and entrance ramps to advise drivers that they must leave the freeway at the next exit. These signs are normally covered by a hinged panel that would have to be manually dropped by state patrol personnel in order to display the warning message.
It is also old in the art to provide TV cameras at strategic locations along a freeway. These cameras are adapted to transmit video data to a highway department facility so that traffic levels, and sometimes traffic violations, can be remotely monitored. The Moore U.S. Pat. No. 5,729,214 describes a remotely controlled message display system having lighted signs that allow a plurality of different messages to be displayed by selected illumination of a plurality of lamps. Such signs frequently are used to indicate levels of congestion, the location of accident scenes, road conditions, etc. A satellite-based communications system is used to transmit data to electronic circuits in the signs themselves to control the wording of the message to be displayed.
The Lemelson et al. U.S. Pat. No. 6,317,058 describes a traffic regulating system also involving geostationary satellites for monitoring traffic flow and controlling traffic lights and warning signs. The patent also teaches the use of video cameras strategically positioned over or next to a roadway along with means for transmitting video data streams to a central site.
Thus, while prior art patents disclose various systems for monitoring and controlling traffic flow that use automated warning signs, traffic monitoring video cameras and wireless communications links, we are not aware of any automatic system operated from a control center for rapidly, safely and automatically rerouting freeway traffic so as to shut down sections of freeway when they become unsafe due to snow and ice conditions, chemical spins, etc. where the control center is located remote from the affected interchanges. The present invention provides such a system.
The present invention comprises a freeway interchange traffic rerouting control system. The system comprises a plurality of motorized, radio-controlled gates that are located at freeway interchanges to selectively block traffic flow onto freeway entrance ramps and on freeway driving lanes, but not on the freeway""s exit ramps. A radio transmitter is placed within range of the motorized radio-controlled gates. Completing the system is a control center having an INTERNET connection to a communications server for permitting authorized persons to cause predetermined coded signals to be transmitted by the radio transmitter to the plurality of radio-controlled gates for controlling the movement of the gates"" barrier arms between a raised and a lowered traffic-obstructing disposition.
As a further embodiment, radio-controlled signs may be positioned up road from the interchange by a predetermined distance or more and when actuated, they provide a warning message to oncoming vehicle drivers when one of the radio-controlled gates receives a coded signal for effecting movement of its barrier arm to its lowered disposition.
Further enhancing the system is a plurality of video cameras that appropriately placed at the interchange to view each of the oppositely directed freeway driving lanes and the entrance ramps. Video data from the cameras is sent via a broadband radio link to a communications server having a connection to the INTERNET, whereby persons at a workstation at the control center may view events taking place at the interchange.
There are, of course, additional features of the invention that will be described hereinafter which will form the subject matter of the appended claims. Those skilled in the art will appreciate that the preferred embodiments may readily be used as a basis for designing other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions since they do not depart from the spirit and scope of the present invention. The foregoing and other features and other advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.